Method for producing shatterproof glass panels and casting resin molding

ABSTRACT

The invention relates to a method for the production of shatterproof glass panes, in which an initial body is provided between the panes and made to form a bond, whereby UV light from a broadband energy source is beamed onto the initial body and whereby the initial body is provided with an IR absorber before UV irradiation, the concentration of which is sufficient in order to absorb IR radiation in the initial body from the broadband energy source during the reaction and to thus accelerate curing.

This invention relates to the subject matter in the preamble of patentclaim 1 and is thus concerned with the production of fastUV-thermosetting substances, such as those used in the production ofshatterproof panes of glass.

Shatterproof glass panes are known per se. As a general rule, theyconsist of two separated panes that are connected via a compoundsituated between them in order to provide a light-weight, shatterproofstructure. The automobile industry already produces shatterproof glassby pouring casting resin between two panes that can be made of flatglass (float glass) and/or plastic. The casting resin is then cured byUV irradiation, which then produces the bond.

In order to achieve a thorough curing, very strong UV emitters andundesirably long irradiation times are required. This increases the costof the composition of shatterproof glass panes and thus limitsusability. The same goes for other uses outside of production ofshatterproof glass panes, in which compounds are changed by UVirradiation.

The object of this invention is to provide an innovation for commercialuse.

The object is solved in the independent claims. Preferred embodimentscan be found in the dependent claims.

Thus, in accordance with the first main aspect of the current invention,a method is suggested for the production of shatterproof glass panes, inwhich an initial body is provided between the panes and made to form abond, whereby UV light from a broadband energy source is beamed onto theinitial body and whereby the initial body is provided with an IRabsorber before UV irradiation in order to absorb IR radiation in theinitial body from the broadband energy source during the reaction and toabsorb heat in the cured compound of the shatterproof glass.

It is important to note here that the curing can be accelerated by thepresence or addition of only a very small amount of infrared absorber.This realization is not limited to the production of shatterproof glasspanes, but does provide particular advantages in that field. Theaddition of an IR absorber to a compound to be cured therebysignificantly reduces the irradiation time with the same hardeningresults, even though the actual curing itself does not take placethrough heating, but rather through a transformation activated inanother field, which offers considerable advantages with respect tosystems engineering and production times. The process thereby takesadvantage of the fact that the typically used energy sources for the UVirradiation of the initial body work in a broadband manner, as is thecase in metal vapor discharge lamps, in particular mercury vapordischarge lamps, whereby UV and IR are irradiated simultaneously.

The initial body thereby typically comprises a compound with aUV-sensitive photoinitiator that has in particular a certain,not-too-low sensitivity to temperature i.e. that runs through thedesired hardening reaction faster and/or different due to UV light atdifferent temperatures. Compounds or photoinitiators particularly suitedfor the purposes of the invention have a large variation in theirsensitivity to temperature.

In a preferred embodiment, the IR absorber is UV resistant in order tobe active over the entire irradiation period, as opposed to thephotoinitiator, which is typically broken down over the course of thecuring or transformation of the initial body. Due to the significant andmeasurable increase in temperature over the course of the reaction dueto the IR absorption, the initial body or the reacting photo-sensitivecomponents of the initial body can compensate for the decrease inconcentration due to the break-down of the photoinitiator such thatincreased reaction speeds result for the respective still remainingamounts of the photoinitiator. Even with low amounts of the suitableabsorber, the heating is already so much faster that it remains limitedat least locally to the initial body, which is advantageous because noor at least no significant coupling of heat into objects to be glued,sealed, or effused takes place, in particular, if they only have a verylow thermal conductivity like those panes typically used forshatterproof glass panes.

It is possible to use casting resin as the initial body, in particularcasting resin based on acrylic or acrylate resin, which is preferredinsofar as such initial bodies for ultraviolet, visible, and infraredlight are sufficiently transparent or can be selected. The preferred useof inorganic infrared absorber is also possible in such compounds,namely in particular using dispersing aids that allow the preferred,very even distribution of particles that are very small in size in orderto thus enable an even coupling of the IR irradiation. The infraredabsorber can and is thus preferably distributed or dispersedhomogeneously.

The IR absorber is preferably a transparent conductive oxide that isequipped with suitable dispersing agents, in particular ATO, ITO, ZnO,LaB6 and/or mixtures of and/or with these substances and/or suchencapsulated substances and/or mixtures. Even with larger concentrationsof these substances, it is possible to select the dispersing additivessuch that the IR absorber remains finely distributed in the initial bodyduring the reaction so that it also absorbs heat in the cured compoundof the shatterproof glass pane and is thus able to provide anothertypically desired property in addition to the acceleration of thehardening reaction and thus the reduction in the cost to produce theshatterproof glass pane. The IR absorber is typically nanoparticulate,i.e. it has sizes ranging from 10 nm to the μm range, each relating totheir individual particle and/or agglomerate thereof in order to thusguarantee good distributability in the casting resin or its pre-stages.

However, in lower quantities, it is exactly these materials that haveideal properties for achieving the desired IR absorption during thereaction; the quantities of these materials can be held low enough inorder to be able to avoid damage to potentially existing surfaces orvolume properties such as static chargeability, transparency for radiowaves, in particular for example, in the GSM bands.

The IR absorbers, initial bodies, and dispersing additives to be usedgreatly depend on the planned use of the panes or other material to beconnected, sealed, or transformed. However, it is understood thatchanging initial bodies may require systems with different dispersingcompounds. In this connection, also note that, in typical systems, theinfrared absorber in this invention can be mixed with the casting resinin any order.

However, acrylates are preferably selected from the following group:1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate,neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate,neopentyl glycol adipat di(meth)acrylate, neopentyl glycolhydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate,dicyclopentenyl di(meth)acrylate modified with caprolactame, phosphoricacid di(meth)acrylate modified with ethylene oxide, cyclohexyldi(meth)acrylate modified with an allyl group, isocyanuratedi(meth)acrylate, trimethylolpropane tri(meth)acrylate,dipentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylatemodified with propionic acid, pentaerythritol tri(meth)acrylate,trimethylolpropane tri(meth)acrylate modified with propylene oxide, tris(acryloxyethyl) isocyanurate, dipentaerythritol penta(meth)acrylatemodified with propionic acid, dipentaerythritol hexa(meth)acrylate,dipentaeryhtritol hexa(meth)acrylate modified with caprolactam,(meth)acrylate ester monofunctional (meth)acrylate, such asmethyl(meth)acrylate, ethyl(meth)acrylate, isopropyl(meth)acrylate,2-ethylhyxyl(meth)acrylate butyl(meth)acrylate,cyclehexyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate,2-hydroxyethyl(meth)acrylate, 2-hydroxy-propyl(meth)acrylate,polyethylene glycol mono(meth)acrylate, methoxypolyethylene glycolmono(meth)acrylate, polypropylene glycol mono(meth)acrylate,polyethylene glycol polypropylene glycolmono(meth)acrylate, polyethyleneglycol polytetramethylene glycol mono(meth)acrylate and glycoldi(meth)acrylate; difunctional (meth)acrylate, such as ethylene glycoldi(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycoldi(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethyleneglycol di(meth)acrylate, polypropylene glycol di(meth)acrylate,neopentyl glycol di(meth)acrylate, allyl(meth)acrylate,bisphenol-A-di(meth)acrylate, ethylene oxide-modifiedbisphenol-A-di(meth)acrylate, polyethylene oxide-modifiedbisphenol-A-di(meth)acrylate, ethylene oxide-modifiedbisphenol-S-di(meth)acrylate, bisphenol-S-di(meth)acrylate,1,4-butandiol di(meth)acrylate, and 1,3-butylene glycoldi(meth)acrylate; and tri- and higher functional (meth)acrylate, such astrimethylol propane tri(meth)acrylate, glycerin tri(meth)acrylate,pentaerythrite tri(meth)acrylate, pentraerythrite tetra(meth)acrylate,ethylene-modified trimethylol propane tri(meth)acrylate,dipentaerythrite hexa(meth)acrylate, 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl acrylate,2-ethylhexyl carbitol acrylate, omega-carboxypoly caprolactammonoacrylate, acryloyloxy ethyl acid, acrylic acid dimer, lauryl(meth)acrylate, 2-methoxy ethyl acrylate, butoxy ethyl acrylate, ethoxyethyl acrylate methoxy triethylene glycol acrylate, methoxy polyetheleneglycol acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate,tetrahydrofurfuryl (meth)acrylate, N-vinyl-2-pyrrolidon, isobornyl(meth)acrylate, dicyclopentenyl acrylate, benzyl acrylate, phenylglycidyl ether epoxy acrylate, phenoxy ethyl (meth)acrylate, phenoxy(poly)ethylene glycol acrylate, nonylphenol ethoxylized acrylate,acryloyloxy ethyl phthalic acid, tribromophenyl acrylate, tribromophenolethoxylized (meth)acrylate, methyl methacrylate, tribromophenylmethacrylate, methacryloxyethyl acid, methacryloyloxyethylhexahydrophthalic acid, methacryloyloxyethylphthalic acid, polyethyleneglycol (meth)acrylate, polypropylene glycol (meth)acrylate, betacarboxyethyl acrylate, N-methylol acrylamide, N-methoxy-methylacrylamide, N-ethoxymethyl acrylamide, N-n-butoxymethyl acrylamide,t-butyl acrylamide sulfonic acid, vinyl stearate, N-methyl acrylamide,N-dimethyl acrylamide, N-dimethylaminoethyl (meth)acrylate,N-dimethylaminopropyl acrylamide, acryloylmorpholine, glycidylmethacrylate, n-butyl methacrylate, ethyl methacrylate, allylmethacrylate, cetyl methacrylate, pentadecyl methacrylate, methoxypolyethylene glycol (meth)acrylate, diethylaminoethyl (meth)acrylate,methacryloyloxyethyl succinic acid, hexanediol diacrylate, neopentylglycol diacrylate, triethylene glycol diacrylate, polyethylene glycoldiacrylate, polypropylene glycol diacrylate, pentaerythritol diacrylatemonostearate, glycol diacrylate, 2-hydroxyethylmethacryloyl phosphate,bisphenol A ethylene glycol adduct actylate, bisphenol F ethylene glycoladduct acrylate, tricyclodecanemethanol diacrylate, trishydroxyethylisocyanurate diacrylate, 2-hydroxy-1-acryloxy-3-methacryloxypropane,trimethylolpropane triacrylate, trimethylolpropane ethylene glycoladduct triacrylate, trimethylolpropane propylene glycol adducttriacrylate, pentaerythritol triacrylate, trisacryloyloxyethylphosphate, trishydroxyethyl isocyanurate triacrylate, modifiedepsilon-caprolactam triacrylate, trimethylolpropane ethoxy triacrylate,glycerol propylene glycol adduct triacrylate, pentaerythritoltetraacrylate, pentaerythritol ethylene glycol adduct tetraacrylate,di-trimethylolpropane tetraacrylate, dipentaerythritolhexa(penta)acrylate, dipentaerythritolmonohydroxy pentaacrylate,urethane acrylate, epoxy acrylate, polyester acrylate, unsaturatedpolyester acrylate.

Furthermore, the photoinitiator can preferably be selected from thefollowing group: benzoin, benzoin methyl ether, benzoin ethyl ether,benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether,acetophenone, dimethylaminoacetophenone,2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenyl-acetophenone,2-hydroxy-2-methyl-1-phenylpropane-1-on, 1-hydroxycyclohexyl phenylketone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1-on,4-(2-hydroxyethoxy)phenyl 2-hydroxy-2-propyl ketone, benzophenone,p-phenylbenzophenone, 4,4′-diethylaminobenzophenone,dichlorobenzophenone, 2-methyl-anthrachinone, 2-ethylanthrachinone,2-tert-butylanthrachinone, 2-aminoanthrachinone, 2-methylthioxanthone,2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone,2,4-diethylthioxanthon, benzyl dimethyl ketal, acetophenone dimethylketal, and p-dimethylamine benzoate.

The quantity of infrared absorber, in particular of transparent,conductive oxide, is typically between 0.005 wt. % and 4 wt. % of thecasting resin molding, whereby even lower amounts hardly contribute tosignificant improvements in the curing time, while with higherconcentrations no additional advantage typically occur, assumingcorresponding layer thicknesses. Moreover, it cannot be excluded thatthe overall stability of the shatterproof glass pane or other systemdoes not remain the same or almost the same as without admixing.

But, particularly for very low concentrations, it is surprising thatprocessing times can be decreased significantly, which in turn leads toan overall reduction in cost. This can then already be the case whensuch a low amount of absorber is used that no significant propertychanges result in the final product based on its presence alone. Itshould be noted that the IR energy flow from conventional UV lamps isconsiderably higher than in normal sunlight, so that good results can beobtained even though the absorption of IR is low for solar irradiation.The actual overall concentration can also be selected depending on theoverall layer thickness and namely also with respect to a later requiredor desired heat absorption or the radiation absorption and/or theelectrostatic properties of the finished shatterproof glass pane.

Protection is also required for a correspondingly equipped shatterproofglass pane as well as, in accordance with the invention, for an equippedcasting resin, in particular a transparent and liquid casting resin, inparticular based on an acrylate or an acrylic, which can, in particular,be consist of acrylic resin, acrylic acid, and methylmethacrylate.Protection is also in great demand for casting resin and otherUV-curable compounds in which the absorber content based on the above,in particular ITO content and/or ATO content of under 0.4%, is inparticular under 0.2%. Casting resins or other UV-transformable systems,which are not used in the production of shatterproof glass panes butwhich offer advantages with respect to very fast transformability withUV light without the addition of IR properties of the end product orsimilarly influential TCO amounts, can be realized with the invention.

The invention is described below using an example that refers tofigures. The figures show the following:

FIG. 1 the transmission through different layer thicknesses of castingresin with different layer thicknesses

FIG. 2 the transmission through a 1-mm-thick layer of casting resin withdifferent contents of indium stannous oxide IR absorber.

COMPARATIVE EXAMPLE

Two panes made of inorganic flat glass are set at a distance of 1 mmfrom either other and sealed on the edges. Then a casting resin from aconventional mixture of acrylic resin, acrylic acid, andmethylmethacrylate is poured into the gap. The fill-in hole is glued.Now the arrangement is exposed to UV light created by a broadband UVenergy source, here a UV curing device made by Beltron. It is determinedhow many irradiation passes at an energy of 5000 mJ/cm2 are needed forcomplete curing. It is determined that eight passes are needed.

EXEMPLARY EMBODIMENT 1

Two glass panes are again arranged at the aforementioned separationdistance and sealed on the edges. 0.1 wt. % ITO is now incorporated intothe casting resin as used before, before the liquid casting resin ispoured between the panes. With corresponding irradiation with passes of,once again, 5000 mJ/cm2 in the UV curing device, only four passes arerequired for complete curing.

Transmission and absorption curves of the finished laminate compoundsare then recorded for different layer thicknesses and ITO contents. FIG.1 shows the results for different wavelengths for different thicknessesof 100 μm, 4.7 mm, and 1 mm. One can see that the transmission in therange of the wavelengths over approx. 1500 nm is significantly lower fortechnically relevant layer thicknesses.

FIG. 2 shows the effect of different indium stannous oxide contents onthe transmission, whereby the uppermost curve shows the transmission ofthe casting resin without the admixture of infrared absorber.

EXEMPLARY EMBODIMENT 2

0.1 wt. % of a nanocrystalline ATO (SnO2:Sb) was incorporated into acasting resin as in exemplary embodiment 1. The transparent liquid waspoured between two glass panes that were sealed on the edges and thathad a separation distance of 1 mm (=gap). After filling the resin, thefill-in hole is glued. The same was done with the unmodified resin. Bothsamples were fed through a UV curing device (Beltron) for curing; thesamples were exposed to an energy of 5000 mJ/cm2 per pass.

In the case of the unmodified resin, 8 passes were need for completecuring. The resin containing the ATP was completely cured after 5passes.

EXAMPLE

An ATO powder is first encapsulated as an IR absorber: 100 g of aconventional ATO powder is pre-dispersed in 500 ml of deionized water.The dispersion is adjusted to a temperature of 75° C. by the dropwiseaddition of an ammonia solution with 2 mol NH3/l and a pH value of 8.5.Then a solution with a reactive orthosilicate is added dropwise to thedispersion under strong acoustic excitation (ultrasound) until theration of orthosilicate to ATO has reached a value of 1:4 after 90minutes. The dropwise addition takes place at a constant temperature anda pH held constant by the addition of a hydrochloric acid solution with2 mol HCl/l. After the end of the dropwise addition, the fluid iscooled, the obtained solid is filtered off, washed and then dried forthree hours at 100° C. The substance produced in this manner is reusedas encapsulated ATO.

0.15 wt. % of this nanocrystalline ATO (SnO2:Sb), which was providedwith a glass-like encapsulation, is incorporated into a casting resin asin exemplary embodiment 1; the share of the encapsulation amounted to 20wt. % of the overall mass of the powder. The resulting transparentliquid was poured between two glass panes that were sealed on the edgesand that were located 1 mm from each other (=gap). After filling in theresin, the fill-in hole was glued. The same was done with the unmodifiedresin.

Both samples were fed through a UV curing device (Beltron) for curing;the samples were exposed to an energy of 5000 mJ/cm2 per pass.

In the case of the unmodified resin, 8 passes were need for completecuring. The resin containing the encapsulated ATO was completely curedafter 5 passes.

Based on the encapsulation, in particular the glass-like encapsulationof the inorganic IR absorber, here nanocrystalline TCO, the curedcompound behaves biologically the same as compounds without suchadditives, so that it can be used for foodstuffs, etc. It is clear thatthe encapsulation is positive for use in foodstuffs, pharmaceuticals, orsimilar areas regardless of the actual encapsulated material, and theadmixture of encapsulated IR absorber for curing or decreasing theirradiation time is advantageous for any UV-transformable compound.

1. Method for producing shatterproof glass panes, in which an initialbody is provided between the panes and made to form a bond, whereby UVlight from a broadband energy source is beamed onto the initial body andwhereby the initial body is provided with an IR absorber before UVirradiation, the concentration of which is sufficient in order to absorbIR radiation in the initial body from the broadband energy source duringthe reaction and to thus accelerate curing.
 2. Method in accordance withclaim 1, characterized in that a UV-resistant absorber is used. 3.Method in accordance with claim 1, characterized in that theUV-resistant absorber is added in an amount that is sufficient in orderto absorb heat in the cured compound of the shatterproof glass pane. 4.Method in accordance with claim 1, characterized in that the panesarranged at a certain separation distance and framed in order to be ableto pour the initial body into the area between the panes.
 5. Method inaccordance with claim 1, characterized in that the compound is curedduring the reaction.
 6. Method in accordance with claim 1, characterizedin that a metal vapor discharge lamp, in particular a mercury vapordischarge lamp, is used as the light source.
 7. Method in accordancewith claim 1, characterized in that an initial body with aphotoinitiator is used.
 8. Method in accordance with claim 1,characterized in that a temperature-sensitive compound and/or atemperature-sensitive photoinitiator is used.
 9. Method in accordancewith claim 1, characterized in that a photoinitiator is used that isbroken down or abreacted during the reaction.
 10. Method in accordancewith claim 1, characterized in that a UV-resistant infrared absorber isused.
 11. Method in accordance with claim 1, characterized in that aninorganic infrared absorber is used.
 12. Method in accordance with claim1, characterized in that a transparent conductive oxide, in particularATO or ITO, is used as the infrared absorber.
 13. Method in accordancewith claim 1, characterized in that the IR absorber is distributedhomogeneously in the initial body, in particular in nanoparticulateform.
 14. Method in accordance with claim 1, characterized in that atransparent initial body, in particular visibly transparent inultraviolet and infrared as well as after reactions, is used. 15.Shatterproof glass pane with panes made of glass and/or plastic and witha cured casting resin between them, characterized in that a particularlynanoparticulate, transparent, conductive oxide is added to the castingresin.
 16. Shatterproof glass pane in accordance with claim 15,characterized in that indium stannous oxide is used as the transparentnanoparticulate oxide, in particular with a particle and/or agglomeratesize between 100 nm and several μm.
 17. UV-curable compound, inparticular a casting resin for the production of shatterproof glasspanes, with a photoinitiator, for the initiation of the curing based onUV irradiation and a dispersed and/or incorporated inorganic infraredabsorber, in particular in concentrations between 0.05 and 0.3 wt. %.18. Method in accordance with claim 2, characterized in that theUV-resistant absorber is added in an amount that is sufficient in orderto absorb heat in the cured compound of the shatterproof glass pane. 19.Method in accordance with claim 2, characterized in that the panesarranged at a certain separation distance and framed in order to be ableto pour the initial body into the area between the panes.
 20. Method inaccordance with claim 3, characterized in that the panes arranged at acertain separation distance and framed in order to be able to pour theinitial body into the area between the panes.